Troubleshooting HMV

Everyone has a different experience with Home Mechanical Ventilation (HMV). Some patients get used to the device easily, whilst others can struggle. Included within this section are some common issues experienced and some tips and suggestions for resolving or improving these.


The mask needs to be correctly fitted and secured with the headgear (straps). Most headgear can be adjusted with velcro straps.  The mask and headgear should be removed and attached with clips or hooks. This allows ease of use, but also ensures the longevity of the Velcro, and therefore the headgear.

There are several mask options available and depends on whether you are predominantly a nose or a mouth breather. The mask needs to be cleaned daily, or poor mask fit and skin irritations may occur. Most masks are vented. This means they have a deliberate leak to prevent rebreathing of air. This should not be occluded. A chin strap can be added to a nasal interface if mouth drop, ie the mouth falling open, during the night is experienced.


Some individuals, such as those with COPD, experience a period of breathlessness when switching off their ventilator. This may happen because of adapting to normal breathing again.

Holding the mask in place and gradually getting used to breathing over a few minutes with some breaths via the HMV and some without the ventilator can be of benefit. Also, some devices may have a ramp down option to allow this to gradually take place.

If there is experience of breathlessness whilst using the HMV, or if it does not provide enough support, then the clinical team should be contacted. For issues that might relate to underlying medical condition(s), the patient’s GP or relevant clinical team should be contacted.


Headaches can be an indicator that carbon dioxide is high. Equally, it can be positional related to a pillow/bed. If this occurs over several mornings and the patient feels that the mask headgear is causing undue pressure from over-tightening, the clinical team should be advised.

Increased Daytime Sleepiness

Increased daytime sleepiness (if using the device each night for the recommended prescription) may indicate that the settings are not correct. Try increasing usage and contact the clinical team regarding this issue.

Some individuals experience thick sticky secretions that are difficult to clear. If this happens, try to increase fluid intake, especially in warmer weather. Check that there is a good mask fit, as significant mask leak can contribute to this problem and contact the clinical team if the symptoms persist. The team may review the mask and consider adding humidification, or prescribing medication to thin the mucus.

Other upper airway symptoms, such as nasal congestion or a runny nose, may also occur because of problems using HMV and the clinical team may be able to help here too.

Mouth Dryness and Nosebleeds

The air delivered by the HMV is room air at a higher flow. If the room temperature is cold, then the increased flow rate can exacerbate this and result in mouth dryness. Other side effects may include nosebleeds. Mouth dryness is especially common for patients who use a nasal mask and open their mouths during sleep.

Solutions include improved mask fitting, alternative mask interfaces, or adding humidification to the circuit. A higher humidifier temperature will increase the humidity, but this depends on personal preference. If the room temperature is cold or a window is open/fan used, then water rainout (condensation accumulated) in the tubing can be problematic.

Why is my nose runny when I put my mask on?

This is a reaction to the airflow. If you have a heated humidifier, try increasing the setting to make the airflow moist. If you do not have a heated humidifier contact your specialist team to request one. If humidification does not help contact your Doctor as you may benefit from some nasal medication.

Why is my nose stuffy when I put on my mask?

Firstly, check that the filter in your machine to see if it is clogged with dust. If it is its likely that dust is being blown through your device and into your mask. This not only makes your nose stuffy but also makes it harder for the motor in your ventilator. Ensure you are drinking well and are not dehydrated. If seasonal, try increasing the frequency of the filter changes or speak with your clinical team about hypoallergenic filters. A stuffy nose can also be a reaction to the airflow. Try increasing the setting on your heated humidifier if you have one. As long as water is not collecting in your tubing it is okay to increase the setting. If you do not have a heated humidifier contact your specialist team to request one. If the stuffy nose continues consult your Doctor.

Sore Eyes in the Morning
My eyes are red and sore in the morning or wake me up because they hurt, what should I do?

This means that your mask is leaking into your eyes and the airflow is causing drying and irritation. Firstly, try loosening the masks straps. As long as the mask is not leaking excessively, you do not need it to be too tight and overtightening can sometimes make it leak more. If this does not work, you may need to try a different mask. Whilst waiting for a new mask, consider sleeping with an eye mask over your eyes to protect them from air leaking. In an emergency, laying a sock over your eyes will provide a temporary solution.

Soreness to the nasal bridge/uncomfortable mask

Faces are not designed for long-term/extended mask use. Soreness to the bridge of the nose is not uncommon. Mask design and fit is important to prevent skin problems from occurring. There are masks that avoid this area and contacting the service provider as soon as the problem is experienced will enable an alternative interface to be found. Contact the clinical team without delay if there is prolonged redness/soreness as it may be the first stage of a pressure sore.

Your specialist team will have assessed which mask is the most appropriate mask for you however you may not always find that the mask suits you when you have to wear it regularly. Most specialist centres will have a range of masks and therefore it is important that you discuss mask problems with them so that they can support you to find the most suitable mask. It may be that you need some additional support with fitting your mask or advice on how best to clean and dry your mask to maintain its comfort. Masks include nasal pillows, nasal, hybrid, full-face, and total. A mask that covers your nose & mouth should be avoided if you feel nauseous and you should be able to remove the mask independently.


Sinusitis is swelling of the lining of the sinuses. The sinuses are areas around the nose that drain mucus to keep the nose clean and healthy.

HMV can cause drying or swelling in the sinus. This is because of the cool room temperature or from direct pressure on the area from airflow or the mask. Using a mask that goes over the nose and mouth (full face mask), hose warmers, putting the hose under a blanket (as long as the expiratory port is kept free) can help to ease this. Often an additional heated humidifier (water bath) attached to the HMV device can help moisten the air. If the sinusitis continues then a medical review may be indicated from your GP.

Liaise with your local team as an increased rise time or reduced pressures may be indicated.
Supplementary Oxygen

Some patients with COPD are sensitive to oxygen such that they may retain excess carbon dioxide if using too much oxygen. Clinical teams usually recommend that such patients aim for target oxygen saturations between 88% and 92%. If oxygen levels are too low, then this is also of concern. Some patients therefore require oxygen added to their HMV circuit overnight and may also require oxygen during the day. This should always be done under the supervision of your HMV team.

A separate oxygen concentrator device is used to provide oxygen to the HMV circuit. The oxygen should not be left running through the HMV device when it is not in use. When turning off the HMV device, the oxygen concentrator must be switched off (or disconnect the oxygen if using oxygen alone during the day).

However, it is important to note that oxygen will be prescribed if required. It is not beneficial unless accompanied by low saturation levels.

Some patients with COPD also require oxygen therapy during the day to maintain oxygen saturations at their target level, again typically 88 – 92%. The clinical team will set the oxygen prescription. The term used to describe this type of oxygen therapy is ‘Long Term Oxygen Therapy.’ Most clinical teams refer to this as LTOT (pronounced L-tot). The oxygen settings (L/min) whilst using HMV might not be the same as the settings used when not using HMV.

It feels like the machine is puffing air faster than I am breathing, what should I do?
Try to relax and see if you can get used to this different way of breathing. Sometimes if you are anxious you may breathe a little faster and the machine will try to keep up with you. Also, if your breathing rate was fast when you were first set up on the HMV machine it may slow down as you get more used to it. You may then need to have your settings adjusted to make it more comfortable and you should liaise with your clinical team.
Power Cuts/Off Grid
If you live off-grid or experience regular power cuts, it is worth contacting your energy supplier to explain that you are a patient at risk and that you use a device that requires constant power. In these situations, the company may be able to provide a generator to support your device if there is a power outage.

If you live off-grid, your healthcare centre should be able to provide you with a second device or set of batteries that you can use if there is no electricity. On the subject of electricity, the cost of running a device is less than the cost of watching television.

Struggling to Clear my Phlegm/Chest Infection

I don’t have a very strong cough and I struggle to clear my phlegm. I’m worried what would happen if I got a chest infection.

In order to cough effectively, you need inspiratory muscles, abdominal & expiratory muscles plus bulbar function (muscles affecting speech & swallowing). Measuring your cough with a peak flow meter (as used with asthma patients) with a cushioned mask can provide an indicator of your cough strength. Above 360l/min is normal, below 270l/min puts you in the amber category & below 160l/min is in the red zone. Most services would advise providing assistance with either a lung volume recruitment (LVR) bag to enable breath stacking or a cough assist (otherwise known as MI/E, mechanical insufflator exsufflator).

These can be used alongside other physiotherapy techniques including postural drainage, percussion & expiratory vibrations. Usually, the pressures can be gradually increased until therapeutic pressures are achieved to prevent any side effects such as bloating & chest wall discomfort. Your clinical team will provide support and training for this device. Ensure you are adequately hydrated and there are medications available to assist with managing secretions depending on the viscosity.